Aesthetic body contour surgery has become a routine procedure by which to increase the attractiveness of the human form. One particular method of body contour surgery, suction lipectomy or liposuction, is a procedure that permits elimination of localized fat deposits through small incisions which leave inconspicuous scars. Liposuction is one of the most common aesthetic procedures performed by plastic and reconstructive surgeons today.
Liposuction has been used to remove fat from many regions of the body. The regions most frequently treated include the trochanteric region, flanks, buttocks, interaspect of the knee, the anterior abdominal wall, gynecomastia, and "love handles." Although it was once believed that the fat cells removed by liposuction would later be replaced, the presently accepted theory is that the body contains a limited number of fat cells which cannot regenerate. Fatty tissue is not caused by an increase in the number of fat cells, but by an increase in the amount of lipid matter found within the cell. Therefore, the removal of fat cells by liposuction should create a contour that will retain its form (absent undue expansion of lipid matter in remaining cells).
Liposuction was first performed in Europe by J. Schrudde in 1972 using a uterine curette. Currently, the procedure is performed using a special type of curette known as a cannula. The cannula is attached to a vacuum source which carries away the fat tissue. The vacuum required is inversely proportional to the size of the suction aperture and the tube diameter (i.e., the smaller the tube and the orifice, the higher the negative pressure needed for the evacuation of the fat). The vacuum pressure in one often used cannula, known as the Aspiradeps, manufactured by Ulrich A. G., in St. Gall, Switzerland, is usually on the order of 0.4 to 0.6 atmospheres.
There are theoretically two different methods by which to remove fat through liposuction. The first of these methods is the tunneling procedure as proposed by Y.-G. Illouz. In the Illouz method, one or two incisions are made. Radial excursions of the instrument into the flesh via the incisions are then made. The result is a multitude of concomitant sinuses. The second method is the original liposuction procedure as proposed by U.K. Kesserling. In the second technique, an entire layer of regular, deep fat is removed, leaving a smooth, deep surface of residual panniculus. The space created is then transformed by compression into a virtual space in which primary healing can take place. Optimally, skin retractions may follow.
Both of the above techniques require the surgeon to push and pull a portion of the cannula back and forth multiple times for each tunnel made. Generally, twenty to thirty tunnels per incision are made to insure even removal of fat in the targeted regions. The surgeon typically massages the flesh in the area of the aperture in the cannula, while at the same time thrusting the rod in and out of the tunnel. This method is extremely traumatic, both for the patient and the doctor. The patient's flesh turns black and blue for several days. Moreover, many surgeons practicing liposuction find it physically exacting, and most come out of the operating room extremely tired after procedures in which large areas are liposuctioned.
It is known from the clinical experience and the work of Kesserling, Illouz, E. H. Courtiss, R. A. Mladick and others, that the sense of aesthetics, symmetry and the amount of trauma human tissue can tolerate must be controlled and guided by an experienced operator and cannot be replaced with currently available machines. Furthermore, clinical observations have led to the opinion that the use of small cannulae leads to less contour deformity and less skin dimpling. Others have felt that the fatigue factor may subtly influence a surgeon's opinion regarding whether he has removed enough fat, while objectively, he would need to continue the process. Automation of the liposuction procedure is, therefore, desirable. Development of an automated liposuction device is therefore desirable.
Several, automated or assisted surgical instruments are currently available for removing biological material. In U.S. Pat. No. 4,735,605 and U.S. Pat. No. 4,792,327, issued to B. E. Swartz, for example, an improved cannula is disclosed. The cannula comprises an outer tube with an elongated aspiration aperture and an inner tube with a spiral slot. A mechanism inside the handle of the device causes the inner tube to rotate, creating a "traveling hole effect" along the elongated aspiration aperture. The "traveling hole effect" is intended to obviate the need to repeatedly push the cannula in and out.
A mechanical apparatus for removing biological material is also disclosed in U.S. Pat. No. 4,735,604 issued to Watmough, et al. Watmough, et al. discloses a device comprising a hollow tubular elongated member mounted for longitudinal sliding movement in a casting. The casting includes a rotatable drive shaft which causes the tubular member, the distal end of which is adapted for removal of biological material, to vibrate at relatively low amplitude and high frequency. The biological material is withdrawn via the tubular member using a negative pressure gradient.
In U.S. Pat. No. 4,705,038 issued to Sjostrom, et al., a single-motor surgical system for operating a set of different surgical devices having different operational limits is disclosed. The system includes a handpiece containing a motor adapted to alternatively receive a proximal portion of several surgical devices, each device provided with an indicator in its proximal portion denoting its operational limits. The handpiece includes an automatic sensor for controlling the motor in accordance with the indicated operational limits of the surgical device currently connected to the handpiece. Each of the plurality of surgical devices preferably includes a vacuum passage adjacent a connectable rotary tip, whereby tissue severed by the rotary tip can be removed from the surgical site.
Automated surgical devices currently available, however, fall far short of providing reliable controlled mechanization of the reciprocal motion required for patient safety and aesthetically pleasing liposuction results. It is therefore desirable and advantageous to develop a device which would safely automate the motion of the cannula to assist the surgeon in the lipectomy procedure by decreasing the physical exertion expended by the surgeon. A device that allows effortless liposuction with a small cannula would allow the surgeon to remove more fat, in a more symmetric and even fashion, and yield an improved aesthetic resulted. The use of smaller cannulae will also reduce trauma to the patient.